Circuit for clamping bridge over-voltages in a voltage-fed quasi Z-source converter

Unlike the voltage source converter, the Z-source converter can boost as well as buck the input voltage. However, the presence of physically large components in the impedance network introduces large parasitic inductances into power device commutation paths. This leads to consequent overvoltages at power device turn-off. A simple circuit for addressing this is presented. Practical results are given for a voltage-fed quasi- Z-source inverter with discontinuous input current

Merging DNA metabarcoding and ecological network analysis to understand and build resilient terrestrial ecosystems

Summary 1. Significant advances in both mathematical and molecular approaches in ecology offer unprecedented opportunities to describe and understand ecosystem functioning. Ecological networks describe interactions between species, the underlying structure of communities and the function and stability of ecosystems. They provide the ability to assess the robustness of complex ecological communities to species loss, as well as a novel way of guiding restoration. However, empirically quantifying the interactions between entire communities remains a significant challenge. 2. Concomitantly, advances in DNA sequencing technologies are resolving previously intractable questions in functional and taxonomic biodiversity and provide enormous potential to determine hitherto difficult to observe species interactions. Combining DNA metabarcoding approaches with ecological network analysis presents important new opportunities for understanding large-scale ecological and evolutionary processes, as well as providing powerful tools for building ecosystems that are resilient to environmental change. 3. We propose a novel ‘nested tagging’ metabarcoding approach for the rapid construction of large, phylogenetically structured species-interaction networks. Taking tree–insect–parasitoid ecological networks as an illustration, we show how measures of network robustness, constructed using DNA metabarcoding, can be used to determine the consequences of tree species loss within forests, and forest habitat loss within wider landscapes. By determining which species and habitats are important to network integrity, we propose new directions for forest management. 4. Merging metabarcoding with ecological network analysis provides a revolutionary opportunity to construct some of the largest, phylogenetically structured species-interaction networks to date, providing new ways to: (i) monitor biodiversity and ecosystem functioning; (ii) assess the robustness of interacting communities to species loss; and (iii) build ecosystems that are more resilient to environmental change

Selective, Catalytic Decomposition of Hydrazine

The selective, catalytic decomposition of hydrazine has been investigated using a 1 wt% Pt-Ni(OH)2 catalyst system quantitatively studied by changing the following parameters; reaction solution alkalinity, temperature, hydrazine concentration, catalyst selectivity, catalyst stability, and catalyst durability. Using sodium hydroxide (NaOH), the best alkalinity was found to be 1 M NaOH. The optimal temperature was found to be 50 °C for complete hydrazine conversion. A hydrazine concentration of 0.1 M produced the most effective reaction. The catalyst was found to be completely selective in hydrogen and nitrogen production with no ammonia formation. The catalyst activity decreased by 15% after 8 days of sitting in air representing relatively poor stability, most likely due to undesired oxidation of the catalyst. Finally, the catalyst activity decreased by about 50% after subsequent, same catalyst reactions showing poor durability, resulting from a reduced number of active reaction sites. Overall, the low noble metal catalyst designed does perform the hydrazine decomposition efficiently with 100% selectivity in hydrogen and nitrogen production but needs an elevated temperature and shows signs of poor stability and durability. The cost effective catalyst could provide basis for future research to create a more stable and durable catalyst that can operate at ambient conditions

Microcytosis and possible early iron deficiency in paediatric inpatients: a retrospective audit.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Iron deficiency anaemia is a common paediatric problem worldwide, with significant neurodevelopmental morbidity if left untreated. A decrease in the mean corpuscular volume (MCV) can be used as a surrogate marker for detecting early iron deficiency prior to definitive investigation and treatment. An audit cycle was therefore undertaken to evaluate and improve the identification, follow-up and treatment of abnormally low MCV results amongst the paediatric inpatients in an English district general hospital. METHODS: The audit cycle was performed retrospectively over two three-month periods (February to April 2006; September to November 2006), amongst patients aged between one month and 16 years that had full blood counts performed whilst admitted on the paediatric ward. Patients with at least one abnormally low MCV result were identified, and their notes reviewed. We looked for any underlying explanation for the result, adequate documentation of the result as abnormal, and instigation of follow-up or treatment. In-between the two audit periods, the results of the first audit period were presented to the medical staff and suggestions were made for improvements in documentation and follow-up of abnormal results. The z-test was used to test for equality of proportions between the two audit samples. RESULTS: Out of 701 inpatients across both audit periods that had full blood counts, 61 (8.7%) had a low MCV result. Only 15% of patients in each audit period had an identifiable explanation for their low MCV values. Amongst the remaining 85% with either potentially explicable or inexplicable results, there was a significant increase in documentation of results as abnormal from 25% to 91% of cases between the first and second audit periods (p = 0.00 using z-test). However, there was no accompanying increase in the proportion of patients who received follow-up or treatment for their abnormal results. CONCLUSION: Abnormal red cell indices that may indicate iron deficiency are frequently missed amongst paediatric inpatients. Medical staff education and the use of appropriate protocols or pathways could further improve detection and treatment rates in this setting

Supporting desistance through ambiguous practice: what can be learned from the first prison-based model of CoSA in England and Wales?

Circles of Support and Accountability (CoSA) are an initiative designed to support those previously convicted of sexual offences as they reintegrate back in to society, whilst still holding them accountable for their thoughts and behaviour (Cesaroni, 2002). The aim of the research was to explore the Core Member and volunteer experience of being involved in a CoSA that transitions from prison to community, with the objective being to focus upon what can be learnt from these initial experiences. The study included qualitative interviews with two separate groups of participants; Core Members (n=7) and volunteers (n=10) involved in the prison-model CoSA. Interpretative Phenomenological Analysis of the data was undertaken to consider the individual’s subjective experience of being involved in this initiative. A superordinate theme of ambiguous practice was identified, whereby volunteers appeared to overlook the importance of expressive support, described a lack of commitment from other fellow volunteers and demonstrated a confusion surrounding the accountability aspect of their role. Despite the confusion highlighted, however, the accountability aspect of the volunteers’ role was identified through their indirect support of Core members’ desistance. The second superordinate theme outlined the volunteers’ encouragement of the Core Members new pro-social lifestyle, thus helping to reinforce their crime -free identity. This led to a concern, however, of what would happen once the CoSA journey had come to an end. The learning derived from these findings can now be used to continue to develop and improve the use of prison-model CoSA across England and Wales

Teaching climate change and sustainability: A survey of teachers in England

This report shares detailed findings as to the current state of climate change and sustainability education in England in 2022-23, with a particular focus on teachers’ practice and professional development. The results reveal both strengths and gaps in the provision of climate change and sustainability education in England. The report serves as an evidence base for researchers, policymakers and practitioners who seek to support teachers to fulfil their important roles in society’s transformation to a sustainable future. UCL’s Centre for Climate Change and Sustainability Education (CCCSE) conducted a survey of teachers in England entitled ‘What do climate change and sustainability education have to do with me?’. Between October and December 2022, teachers were invited to respond to an online questionnaire about their views and experiences. Teachers were recruited through email lists, professional networks, social media and via the CCCSE website. The questionnaire investigated their teaching practice, professional development, and sense of confidence and preparedness to incorporate climate change and sustainability into their teaching. It included a range of question types and generated quantitative and qualitative data. The survey gathered 870 responses, with over two thirds (70.7%) teaching at secondary level, and geography (41.3%) and science (37.2%) being the most frequently reported subjects taught. Those who responded represented a wide range of teaching experience, from one year to 20+ years, with university-led PGCE programmes the most commonly reported route into teaching (87.2%). The significant majority of respondents were female (73.9%) and from white backgrounds (90.5%)

'This time it's different' preparing for release through a prison-model of CoSA: a phenomenological and repertory grid analysis

Circles of support and accountability (CoSA) in the prison-model begin prior to the core members' release from prison and continue with them on release in to the community. The purpose of this study was to explore the expectations of release of those convicted of a sexual offence and how this develops during their participation in the prison sessions of CoSA. The research question was to consider how the prison-model of CoSA relates to the desistance of crime, in particular the phases of desistance developed by Gobbels, Ward and Willis' (2012). Data was collected using both phenomenological interviews and repertory grids at two different time points; prior to starting the circle in prison (n=9) and just before release (n=5). The findings suggest the prison sessions provide a sense of support and 'no longer being alone' often absent in those who sexually offend. The additional prison sessions enabled the participants to experience this during their approaching release date; a stressful period that was characterised by anxiety. Further research is now required to explore whether circles in the prison-model are able to encourage and reinforce the cognitive change required for desistance, enabling the core members to successfully manage their underlying anxieties surrounding societal stigmatisation